If you can access the controller then it means the Ethernet controller is working fine and I doubt there is any hardware defect. All OpenSprinkler units have been tested, and the initial RTC time was obtained through NTP, so that we can verify the Ethernet controller is working and can successfully retrieve data from NTP server. I still suspect this has to do with your particular network setup.
If you want to send back and let us take a look to see if there is any hardware problem, feel free to send a support ticket and we will continue there.